Sealing label

1. A combination of a package and substantially transparent sealing label attached to the package, the label comprising: a carrier layer and an adhesive layer, wherein the label comprises a wavelength conversion layer, which comprises a fluorescent substance, wherein the label comprises a substantially transparent modulating structure to provide a machine-detectable pattern when the label is illuminated with excitation light, wherein the modulating structure comprises one or more spectrally filtering regions positioned above the fluorescent wavelength conversion layer, wherein the filter regions locally prevent propagation of excitation light to the fluorescent wavelength conversion layer.

2. The combination of claim 1 , wherein the label comprises a waveguide, which comprises a fluorescent substance.

3. The combination of claim 2 , wherein the label comprises one or more out-coupling elements to couple waveguided light out of the waveguiding conversion layer.

4. The combination of claim 1 wherein the thickness of the wavelength conversion layer is in the range of 5% to 80% of the total thickness of the label.

5. The combination of claim 1 , wherein the modulating structure provides a target pattern for image recognition.

6. The combination of claim 1 wherein fluorescence quantum yield of the label depends on transverse position.

7. The combination of claim 1 , wherein optical transmittance of the label at the wavelength of 650 nm is higher than 80% in at least 90% of the area of the label.

8. The combination of claim 1 wherein optical transmittance of the label in a wavelength range of 500 nm to 700 nm is higher than 80% over a region, which represents 90% of the area of the label.

9. The combination of claim 1 , wherein the label comprises one or more perforations.

10. A method, comprising providing a combination of a package and a substantially transparent sealing label attached to the package, wherein the label comprises a carrier layer and an adhesive layer, wherein the label comprises a wavelength conversion layer, which comprises a fluorescent substance, wherein the label comprises a substantially transparent modulating structure to provide a machine-detectable pattern when the label is illuminated with excitation light, wherein the modulating structure comprises one or more spectrally filtering regions positioned above the fluorescent wavelength conversion layer, wherein the filter regions locally prevent propagation of excitation light to the fluorescent wavelength conversion layer, the method further comprising: illuminating the label with excitation light so as to cause the label to emit fluorescence light, capturing an image of the label by using an imaging unit, and analyzing the captured image.

11. The method of claim 10 , wherein the label comprises awaveguide, which in turn comprises a fluorescent substance, the method comprising detecting fluorescence light, which is coupled of the waveguiding layer by an out-coupling element.

12. The method of claim 10 , comprising determining the position of the label by analyzing the captured image.

13. The method of claim 10 , comprising capturing the image in a spectrally selective manner, by using an optical filter to prevent propagation of one or more spectral components of light from the label to the image sensor of the camera.

14. The method of claim 10 , wherein the imaging unit comprises a plurality of first detector pixels to provide a first component image by detecting fluorescence light, wherein the imaging unit further comprises a plurality of second detector pixels to provide a second component image by detecting light reflected and/or scattered from the package, wherein the first detector pixels have a first spectral response, and the second detector pixels have a second different spectral response.

15. The method of claim 10 , comprising checking whether the adhesive layer of the label is properly in contact with the package, by comparing the captured image with reference data.

16. A combination of a package and substantially transparent sealing label attached to the package, the label comprising: a carrier layer and an adhesive layer, wherein the label comprises a wavelength conversion layer, which comprises a fluorescent substance, wherein the label comprises a substantially transparent modulating structure to provide a machine-detectable pattern when the label is illuminated with excitation light, wherein the modulating structure has a first concentration of the fluorescent substance at a first transverse position and a second concentration of the fluorescent substance at a second transverse position.

17. A combination of a package and substantially transparent sealing label attached to the package, the label comprising: a carrier layer and an adhesive layer, wherein the label comprises a wavelength conversion layer, which comprises a fluorescent substance, wherein the label comprises a substantially transparent modulating structure to provide a machine-detectable pattern when the label is illuminated with excitation light, wherein a fluorescent layer of the modulating structure has a first thickness at a rust transverse position and a second thickness at a second transverse position.

18. A method, comprising providing a combination of a package and a substantially transparent sealing label attached to the package, wherein the label comprises a carrier layer and an adhesive layer, wherein the label comprises a wavelength conversion layer, which comprises a fluorescent substance, wherein the label comprises a substantially transparent modulating structure to provide a machine-detectable pattern when the label is illuminated with excitation light, wherein the modulating structure has a rust concentration of the fluorescent substance at a first transverse position and a second concentration of the fluorescent substance at a second transverse position, the method further comprising: illuminating the label with excitation light so as to cause the label to emit fluorescenee light, capturing an image of the label by using an imaging unit, and analyzing the captured image.

19. A method, comprising providing a combination of a package and a substantially transparent sealing label attached to the package, wherein the label comprises a carrier layer and an adhesive layer, wherein the label comprises a wavelength conversion layer, which comprises a fluorescent substance, wherein the label comprises a substantially transparent modulating structure to provide a machine-detectable pattern when the label is illuminated with excitation light, wherein a fluorescent layer of the modulating structure has a first thickness at a first transverse position and a second thickness at a second transverse position, the method further comprising: illuminating the label with excitation light so as to cause the label to emit fluorescence light, capturing an image of the label by using an imaging unit, and analyzing the captured image.